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Objective@#To recover broad-neutralizing monoclonal antibodies (BnAbs) from avian influenza A (H5N1) virus infection cases and investigate their genetic and functional features.@*Methods@#We screened the Abs repertoires of expanded B cells circulating in the peripheral blood of H5N1 patients. The genetic basis, biological functions, and epitopes of the obtained BnAbs were assessed and modeled.@*Results@#Two BnAbs, 2-12D5, and 3-37G7.1, were respectively obtained from two human H5N1 cases on days 12 and 21 after disease onset. Both Abs demonstrated cross-neutralizing and Ab-dependent cellular cytotoxicity (ADCC) activity. Albeit derived from distinct Ab lineages, , V 1-69-D2-15-J 4 (2-12D5) and V 1-2-D3-9-J 5 (3-32G7.1), the BnAbs were directed toward CR6261-like epitopes in the HA stem, and HA I45 in the hydrophobic pocket was the critical residue for their binding. Signature motifs for binding with the HA stem, namely, IFY in V 1-69-encoded Abs and LXYFXW in D3-9-encoded Abs, were also observed in 2-12D5 and 3-32G7.1, respectively.@*Conclusions@#Cross-reactive B cells of different germline origins could be activated and re-circulated by avian influenza virus. The HA stem epitopes targeted by the BnAbs, and the two Ab-encoding genes usage implied the VH1-69 and D3-9 are the ideal candidates triggered by influenza virus for vaccine development.
RESUMO
<p><b>OBJECTIVE</b>To investigate the expressions of stromal cell-derived factor-1 (SDF-1) and CX chemokine receptor-4 (CXCR-4) in patients with hepatocellular carcinoma (HC) and liver cirrhosis.</p><p><b>METHODS</b>Peripheral blood and/or ascites fluid were collected from 39 hepatocellular carcinoma patients, 16 patients with liver cirrhosis, 12 with hepatitis and 12 healthy donors. The SDF-1 expression was assayed by ELISA and CXCR-4 was measured by immunohistochemical methods.</p><p><b>RESULTS</b>The level of SDF-1 expression in the carcinoma patients was higher than that of the liver cirrhosis, hepatitis patients and healthy donors, but there was no significant difference between those of the healthy donors and hepatitis patients or liver cirrhosis patients. The levels of CXCR-4 expression were closely related to the tumor differentiation.</p><p><b>CONCLUSION</b>The expression of SDF-1 in the peripheral blood and the CXCR4 expression in the HCC tissues of the HC patients may be regarded as markers of HC and they may have a positive relationship with the differentiation and metastasis of HC.</p>